Plexbmc helper terminates when trying to connect from Android

[sz8638]

I have a fresh Openelec 6.0.0 setup with Amber skin and PLEXbmc addon and plexbmc.helper.
Plex server is installed on a separate box in same subnet.
When trying to connect from Plex Android app, I get an error message, asking to check the log file:

19:40:08 985.910034 T:1617949760 NOTICE: PleXBMC -> Reading settings configuration
19:40:09 986.766296 T:1617949760 NOTICE: PleXBMC -> Running PleXBMC: 4.0.0~beta4
19:40:09 986.766907 T:1617949760 NOTICE: PleXBMC -> Debug is turned off. Running silent
19:40:09 986.853027 T:1626338368 NOTICE: setting: client_id is :
19:40:09 987.367249 T:1626338368 NOTICE: Previous line repeats 1 times.
19:40:09 987.367493 T:1626338368 ERROR: /storage/.kodi/addons/script.module.requests/lib/requests/packages/urllib3/util/ssl_.py:100: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
19:40:10 988.457520 T:1626338368 ERROR: Previous line repeats 1 times.
19:40:10 988.461243 T:1626338368 NOTICE: HTTP response error: 422
19:40:10 988.479858 T:1626338368 ERROR: EXCEPTION Thrown (PythonToCppException) : -->Python callback/script returned the following error<--
- NOTE: IGNORING THIS CAN LEAD TO MEMORY LEAKS!
Error Type: <type 'exceptions.AttributeError'>
Error Contents: 'NoneType' object has no attribute 'text'
Traceback (most recent call last):
File "/storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/default.py", line 13, in
plexbmc.start_plexbmc()
File "/storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/resources/lib/plexbmc.py", line 4105, in start_plexbmc
manage_window.start()
File "/storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/resources/lib/plex_signin.py", line 242, in start
self.gather_plex_information()
File "/storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/resources/lib/plex_signin.py", line 247, in gather_plex_information
user = self.plex_network.get_myplex_information()
File "/storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/resources/lib/plex.py", line 624, in get_myplex_information
date= xml.find('joined-at').text
AttributeError: 'NoneType' object has no attribute 'text'
-->End of Python script error report<--
19:48:27 1485.177246 T:1617949760 ERROR: /storage/.kodi/addons/script.module.requests/lib/requests/packages/urllib3/util/ssl_.py:100: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
19:48:28 1486.291992 T:1617949760 NOTICE: HTTP response error: 401 Unauthorized
19:48:49 1506.925903 T:1617949760 ERROR: /storage/.kodi/addons/script.module.requests/lib/requests/packages/urllib3/util/ssl_.py:100: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
19:52:19 1717.533325 T:1547695168 ERROR: Previous line repeats 2 times.
19:52:19 1717.533569 T:1547695168 NOTICE: Thread LanguageInvoker start, auto delete: false
19:52:19 1717.534912 T:1559999552 NOTICE: Thread JobWorker start, auto delete: true
19:52:19 1717.583008 T:1617949760 NOTICE: ===== PLEXBMC STOP [id: 1450122007.87]: 732.03454113 seconds =====
19:52:19 1717.611694 T:1617949760 ERROR: CPythonInvoker(9, /storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/default.py): failed to run the gc to clean up after running prior to shutting down the Interpreter
19:52:19 1717.612671 T:1617949760 WARNING: CPythonInvoker(9, /storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/default.py): the python script "/storage/.kodi/addons/plugin.video.plexbmc-4.0.0beta4/default.py" has left several classes in memory that we couldn't clean up. The classes include: N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui12ControlLabelE,N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui14ControlTextBoxE,N9XBMCAddon7xbmcgui13ControlButtonE,N9XBMCAddon7xbmcgui11ControlEditE,N9XBMCAddon7xbmcgui12ControlLabelE,N9XBMCAddon7xbmcgui13ControlButtonE,N9XBMCAddon7xbmcgui13ControlButtonE,N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui12ControlLabelE,N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui13ControlButtonE,N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui11ControlEditE,N9XBMCAddon7xbmcgui12ControlImageE,N14PythonBindings33XBMCAddon_xbmcgui_Window_DirectorE,N9XBMCAddon7xbmcgui12ControlLabelE,N9XBMCAddon7xbmcgui12ControlImageE,N9XBMCAddon7xbmcgui13ControlButtonE,N9XBMCAddon7xbmcgui13ControlButtonE
19:52:20 1717.715820 T:1547695168 NOTICE: -->Python Interpreter Initialized<--
19:52:34 1731.730835 T:1547695168 NOTICE: Thread LanguageInvoker start, auto delete: false
19:52:34 1731.905396 T:1547695168 NOTICE: Previous line repeats 2 times.
19:52:34 1731.905640 T:1547695168 NOTICE: -->Python Interpreter Initialized<--
19:52:34 1732.202271 T:1547695168 NOTICE: Previous line repeats 1 times.

Interestingly, the remote control function from the Plex app works ok.

Any idea what I can do about it?